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Production of acid- vs. rennet-curd fresh cheese varieties
Veselá, Vendula ; Suská, Alžběta (referee) ; Vítová, Eva (advisor)
This bachelor thesis‘ focus is on the production and characterization of fresh cheese. Model samples of fresh cheese were produced on VUT Brno using purely acidic curdling (cream cheese culture – lactic acid), combined curdling (cream cheese culture + rennet) and acidic combined with heat curdling (acetic acid. 92 C) The samples were observed for their content of bound and free fatty acids, volatile (aromatic) substances and for their sensory quality. The goal was to determine the influence of the method of curdling on the observed factors. The fats were extracted from the samples using a mixture of diethyl ether and petroleum ether solvents. The fatty acids were esterified with acid to methyl esters under boron trifluoride catalysis and identified by the GC-FID method. In the cheese curdled by combined curdling, a greater amount of free fatty acids was detected compared to the other samples. No significant difference in the amount of bound fatty acids was observed. The greatest fatty acid content overall was observed in the cheese produced by acidic curdling. For identification and semi-quantification of the volatile (aromatic) substances, an HS-SPME-GC-MS method was used. 72 volatile compounds were identified in the samples. The percentual representation of different chemical groups varied significantly, the highest number of volatile substances was observed in the cheese produced by acidic curdling. Sensory evaluation was conducted using an evaluation scale as well as a ranking test. In all the observed indicators, the commercial sample was evaluated the best. The cheese produced by combined curdling was received rather negatively due to the sour taste. The second-best cheese was ranked to be the cheese produced by acidic curdling. The results show that the acidic curdling is the best for taste as well as aromatic substance and fatty acid content. If we, however, consider other factors such as the time taken, the cheese produced by combined curdling appears to be the best overall.
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Production of acid- vs. rennet-curd fresh cheese varieties
Veselá, Vendula ; Suská, Alžběta (referee) ; Vítová, Eva (advisor)
This bachelor thesis‘ focus is on the production and characterization of fresh cheese. Model samples of fresh cheese were produced on VUT Brno using purely acidic curdling (cream cheese culture – lactic acid), combined curdling (cream cheese culture + rennet) and acidic combined with heat curdling (acetic acid. 92 C) The samples were observed for their content of bound and free fatty acids, volatile (aromatic) substances and for their sensory quality. The goal was to determine the influence of the method of curdling on the observed factors. The fats were extracted from the samples using a mixture of diethyl ether and petroleum ether solvents. The fatty acids were esterified with acid to methyl esters under boron trifluoride catalysis and identified by the GC-FID method. In the cheese curdled by combined curdling, a greater amount of free fatty acids was detected compared to the other samples. No significant difference in the amount of bound fatty acids was observed. The greatest fatty acid content overall was observed in the cheese produced by acidic curdling. For identification and semi-quantification of the volatile (aromatic) substances, an HS-SPME-GC-MS method was used. 72 volatile compounds were identified in the samples. The percentual representation of different chemical groups varied significantly, the highest number of volatile substances was observed in the cheese produced by acidic curdling. Sensory evaluation was conducted using an evaluation scale as well as a ranking test. In all the observed indicators, the commercial sample was evaluated the best. The cheese produced by combined curdling was received rather negatively due to the sour taste. The second-best cheese was ranked to be the cheese produced by acidic curdling. The results show that the acidic curdling is the best for taste as well as aromatic substance and fatty acid content. If we, however, consider other factors such as the time taken, the cheese produced by combined curdling appears to be the best overall.
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Vliv způsobu odkalení moštů na výslednou jakost vín révy vinné
Suská, Alžběta
The diploma thesis dealt with the influence of deselination on the quality of wine. In the theoretical part were used various methods of deselination and bentonite use were described. Furthermore, terms such as clarification or the intensity of deselination were explained. In the experimental part, an experiment was performed on two grapevine varieties. Seven different deselination methods have been developed for each variety. It has been monitored the influence of deselination methods on the proces of fermentation, on the weight of sludge after fermentation. Furthermore, the individual wines were evaluated sensorycally, analytically and the results statistically evaluated. Sensorycal evaluation was carried out on a hundred-point scale, and aromatic wine profiles were created. Chemical analysis was performed on FTIR Alpha and Miura One. The most suitable statistical method was chosen for the results.
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Vliv odkalení moštu na kvalitu výsledného vína
Suská, Alžběta
This bachelor thesis deals with influence of desalination method of juice upon quality the resulting wine. Primal used analysis method is senzoritical profile of wine made from vine grapes. The teaoretical part deals with contend of substances in the vine juice, deselination and clarification of juice. The experimental part describe practical attempt of production of four examinated samples made from two different vine grape species. Each sample had differend level of deselination. Reseach was focused upon the influence of desalination level over the fermentation proces and resulting sensoritical profile of produced wine. For evaluation of sensoritical profile was used OIV meridian systém. Research also incudes statistical evaluation and interpreted research conclusion of results from each variation of attempts. Experiment results has proven that wine created from more deselinated juice has better quality. Experiment also proved that optimal deselination of juice is in between 100 - 250 NTU.
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